1. Field of the Invention
This invention relates generally to optical components such as those used in consumer products; and more particularly to aspherical lenses.
2. Description of the Related Art
Aspherical lenses are widely used in aspherical lens systems of vidicons, cameras and so on. U.S. Pat. No. 5,861,999 discloses a conventional aspherical lens system. The aspherical lens system comprises a plurality of aspherical lens units. Each aspherical lens unit comprises two aspherical lenses with a clearance defined therebetween. A chromatic aberration of the aspherical lens unit can be adjusted by adjusting the clearance. U.S. Pat. Nos. 5,557,472 and 5,513,045 also disclose such conventional aspherical lens systems.
Optical characteristics of each aspherical lens unit are determined in large part by the physical geometry of each of the aspherical lenses thereof. If either aspherical lens is imprecisely formed, this can result in an unacceptably high chromatic aberration effect. Furthermore, the aspherical lens system comprising a plurality of aspherical lens units is relatively bulky and heavy, and unsuited for miniaturized applications.
Therefore, a new kind of aspherical lens that overcomes the above-described problems is desired.